近20年全球总云量变化趋势分析

利用ISCCP月平均云气候资料集的总云量资料, 采用趋势分析的方法, 得到1983年7月至2001年9月近20年来全球平均总云量的变化趋势, 并分析云量变化的可能原因。近20年全球增温幅度加快, 研究这期间云的变化, 对气候研究和模拟具有重要的意义。结果表明:平均大气环流决定总云量的分布;全球平均总云量的变化趋势在20世纪80年代末发生逆转, 即由增加转为减少;全球平均云量呈减少的变化趋势, 2000年与1987年相比, 减少量约占平均总云量的4%;从地理位置上看, 云量的变化存在区域性差异, 热带和中纬度地区的总云量减少较多, 高纬度地区云量略有增加, 其中南极大陆云量增加较多。

Analyses of Global Total Cloud Amount Variation over the Past 20 Years

Cloud plays a crucial role through modulating the radiation budget and water cycles in the earth's climate system,thus influences the climate significantly. Global warming accelerates over the past 20 years,analyzing global cloud amount variation during this period can not only promote the understanding to the interaction between the cloud and climate but also help to guide the development of the climate model.By investigating the International Satellite Cloud Climatology Project(ISCCP) D2 dataset,results show that the cloud amount distribution is mainly affected by the atmospheric circulation,and the global mean total cloud amount is about 67%;increasing trend of global annual mean cloud amount reverses in 1987 and there is a decrease trend for global mean total cloud amount with the deduction of about 4% from 1987 to 2000;also,the cloud amount distribution takes on remarkable regional features,which tends to decrease in most tropical and mid-latitude areas while increase slightly in high-latitude,especially over the Antiarctic.